Rocker arm assembly in pump



July 21, 1964 3,141,417

C. W. NORBERG ETAL ROCKER ARM ASSEMBLY IN PUMP Filed Feb. 28, 1963 INVENTORS Gzr/dM/Yorezy & mil/[W flickin ATTORNEY United States Patent 3,141,417 ROCKER ARM ASSEMBLY IN PUMP Carl W. Norberg and Dimitar Tosehkolf, Flint, Mich., assignors to General Motors Corporation, Detroit, Mich., a corporation of Delaware Filed Feb. 28, 1963, Ser. No. 261,603 6 Claims. (Cl. 103150) This invention relates to pumps and more particularly to a rocker arm assembly in a diaphragm type pump and for actuating a pumping diaphragm.

In diaphragm type automotive fuel pumps, it has been customary to utilize rocker arms driven by engine camshafts for actuating the pumping diaphragms. The arm of a given pump would be mounted on a pivot pin and this pin has customarily been supported on the pump body casting in a bore extending through the latter. This has given rise to leakage and many expedients have been utilized to avoid the difficulty. A pump mounted in a bore, as described, is shown in the United States Patent No. 2,036,452, granted April 7, 1936, in the names of A. M. Babitch and G. W. Harry.

An object of the present invention is to provide a diaphragm type pump with an improved rocker arm assembly facilitating manufacture and rebuilding of the pump.

A feature of the present invention is a diaphragm type pump having grooves with closed ends formed in a mounting face of the pump, a pivot pin being retained in the grooves by slugs.

This and other important features of the invention will now be described in detail in the specification and then pointed out more particularly in the appended claims.

In the drawings:

FIGURE 1 shows an elevation view of a fuel pump as operatively related with an engine camshaft and portions being broken away better to illustrate the invention;

FIGURE 2 is a view looking in the direction of the, arrows 2-2 in FIGURE 1;

FIGURE 3 is an enlarged sectional view looking in the direction of the arrows 33 in FIGURE 2; and

FIGURE 4 is an enlarged sectional view looking in the direction of the arrows 4-4 in FIGURE 2.

The pump of FIGURE 1 is much like that disclosed in the United States application for Letters Patent Serial No. 239,694, filed November 23, 1962, in the name of D. Toschkoff. Its interior passages and pumping parts are identical with those of the patent application but the mounting of a rocker arm and pivot pin 12 in the pump constitutes the improved pump and rocker arm assembly of the present invention. The pump includes a pump support casting 14 having a mounting face 16, and a main pump assemblage 20 cooperating with the casting 14 in clamping the periphery of a pumping diaphragm 22. A plunger 24 is provided in combination with a spring and washer arrangement 26 to be operated by a slotted end 28 of the rocker arm 10. A cam 30 on an engine camshaft 32 is adapted to oscillate the arm about the pin 12 and thereby actuate the pumping diaphragm 22 during its suction stroke by means of the plunger 24 as will be understood.

The mounting face 16 is adapted to be clamped against the outer wall of an engine crankcase with a sealing gasket interposed and a surface 34 of the arm 10 resiliently held against the cam 30.

The support casting is apertured as at 36 to receive the arm 10 and two grooves 38 and 40 are formed in axial alignment in the support casting 14. These grooves have closed ends 42 and 44 and are adapted to retain the opposite end portions of the pivot pin 12. The pin 12 is held within the grooves by two slugs 48 and 50 located within recesses 52 and 54 respectively of the casting 14.

3,141,417 Patented July 21, 1964 ice Preferably the recesses 52 and 54 and the slugs 48 and 50 are so proportioned that, after pump assembly, the outer surface of each slug will not be flush with the surface 16 but will be spaced inwardly a slight distance as shown in FIGURE 4. This is to prevent any inadvertent interference of each slug with the sealing of the pump. against the engine. Each slug, however, may be flush with the surface 16 while practicing the present invention, if such construction is desired.

Each recess 52 and 54 is preferably made with a 3 taper to facilitate casting and no surface in the recess need be rough. It can be smooth and polished which is surprising as will further appear as the description proceeds. The recesses 52 and 54 could be undercut but such construction would add to the expense and is not essential.

In forming the assembly, the rocker arm 10 (with the pin 12 inserted therein and rotatable with relation thereto) is inserted into the aperture 36 until the pin 12 rests solidly in the recesses 38 and 40 and the forked end 28 properly engages the spring and washer arrangement 26. Two slugs of a metal which is relatively soft are then snugly placed in the recesses 52 and 54 and a suitable tool is used to strike the slugs and form indentations therein such as shown at 60. This causes the slug metal to flow and snugly engage the pin 12 as at zones A, B, and C. This locks the pin nonrotatively in place. Aluminum, brass, copper, or zinc may be used for the slug material in achieving excellent swedging or staking action. The support casting 16 may be of aluminum, magnesium, or zinc or any metal compatible with the use.

The following variations are permissible without foregoing the advantages:

(1) A blunt instrument will adequately secure the slug;

(2) A hollow cup form of slug may be used in place of a solid cylindrical piece as illustrated so that only one indentation in a slug is necessary;

(3) The pin recesses need not have rough wall surfaces; and

(4) Metal extrusion at the pin ends (A) is not essential although it is preferred.

It is believed that a minimum pull out force of 40 pounds is essential to dislodge the pin and this force may be easily and greatly exceeded in practicing the present invention. The use of a fuel pump body before wheelabrating (a body with a highly polished slug recess with a maximum diameter of .406 inch and a 1 /2 cast draft) has resulted in a pull out force of pounds with an aluminum slug diameter of .400 inch and a pin diameter of .2447 inch in grooves of .246 inch diameter.

The pump may be repaired or reassembled many times but the slugs 48 and 54), if the arm 10 is removed, must be replaced each time. This is easily done and the pin mounting is as new. If the metal of the casting 14 were peened over, the pull out force would be much limited and a given worn pump could not be made fully equivalent to new.

We claim:

1. A diaphragm type pump having an aperture and a rocker arm extending from the latter, a pivot pin retained in grooves formed in said pump on opposite sides of said aperture, said rocker arm being pivoted on said pin, recesses formed in said pump to overlap said grooves, and metal slugs forced into said recesses and into engagement with said pin to hold the latter in firm nonrotative position in said pump.

2. A diaphragm type pump as set forth in claim 1, said recesses being in a casting forming a supporting part of said pump, said recesses being tapered to facilitate casting of the said part.

3. A diaphragm type pump having a support casting with an aperture extending therein, a rocker arm extending from said aperture, grooves formed in said casting on opposite sides of said aperture, a pivot pin retained in said grooves, said rocker arm being pivoted on said pin, recesses in said support casting and overlapping said grooves, and metal slugs forced into said recesses and into engagement With said pin to hold the latter in firm nonrotative position in said support casting.

4. A pump as set forth in claim 3, said recesses being tapered.

5. A diaphragm type pump as set forth in claim 3, said slugs being of metal softer than that of said pin and being substantially cylindrical.

6. A diaphragm type pump having a support casting with a mounting face, an aperture extending into said casting from said face, aligned grooves in said casting and on opposite sides of said aperture, a pin retained in said grooves, a rocker arm pivoted on said pin for actuating said pump, recesses extending from said face into said casting and overlapping said pin and grooves, and a soft metal slug forced into each of said recesses tightly to engage said pin.

No references cited. 

1. A DIAPHRAGM TYPE PUMP HAVING AN APERTURE AND A ROCKER ARM EXTENDING FROM THE LATTER, A PIVOT PIN RETAINED IN GROOVES FORMED IN SAID PUMP ON OPPOSITE SIDES OF SAID APERTURE, SAID ROCKER ARM BEING PIVOTED ON SAID PIN, RECESSES FORMED IN SAID PUMP TO OVERLAP SAID GROOVES, AND METAL SLUGS FORCED INTO SAID RECESSES AND INTO ENGAGEMENT WITH SAID PIN TO HOLD THE LATTER IN FIRM NONROTATIVE POSITION IN SAID PUMP. 